Abstract:

Objective   To explore the effects of preparation technique and obturation technique on the sealing of root fillings in moderately and severely curved root canals. Methods   Sixty curved human premolar teeth were randomly divided into four experimental groups (A、B、C、D) and two control groups(E、F)， in which each experimental group included twelve samples and each control group included six samples. Groups A and C were prepared with the ProTaper/crown-down technique. Groups B and D were prepared with the step-down technique. Groups A and B were obturated with AH-plus sealer by lateral condensation and group C and D were obturated with AH-plus sealer by vertical condensation. We measured the leakage by the concentration of glucose in the apical reservoir along the root filling with O-TB method. Results    The concentrations of glucoes in the four experimental groups were 3.69±1.01、4.59±0.98、2.86±0.82 and 3.70±0.62mmol/L, respectively, while the highest concentration was in group E (5.89±1.69mmol/L).  No glucose was detected in group F. The difference between the step-back and ProTaper/crown-down technique, combined with the same obturation technique, was significant (P＜0.05). The difference between the vertical and lateral condensation technique was significant when the same preparation technique was applied altogether (P＜0.05).Conclusion   The sealing ability of ProTaper/crown-down technique and vertical condensation technique is the best for curved teeth in vitro.

Key words: Curved root canals; Sealing ability; Preparation technique; Obturation technique； O-TB method